Efficiency of Salicornia neei to Treat Aquaculture Effluent from a Hypersaline and Artificial Wetland

Abstract

In this study, we evaluated the potential of Salicornia neei, a halophyte plant native to South America, to treat saline effluents with simulated concentration of ammonium-N (Amm) and nitrate-N (Nit) in a similar manner to land-based marine aquaculture effluents. Plants were cultivated for 74 days in drainage lysimeters under three treatments of seawater fertilized with: (1) Nit + Amm, (2) Nit, or (3) without fertilizer (Control). Over five repetitions, nitrogen removal efficiency (RE) was high in both treatments (Nit + Amm = 89.6% ± 1.0%; Nit 88.8% ± 0.9%), whereas the nitrogen removal rate (RR) was nonlinear and concentration-dependent (RRday1–4: Nit + Amm = 2.9 ± 0.3 mg L−1 d−1, Nit = 2.4 ± 0.5 mg L−1 d−1; RRday5–8: Nit + Amm = 0.8 ± 0.2 mg L−1 d−1, Nit = 1.0 ± 0.2 mg L−1 d−1). Effluent salinity increased from 40.6 to 49.4 g L−1 during the experiment, with no observed detrimental effects on RE or RR. High nitrogen removal efficiency and significant biomass production were observed (Nit + Amm = 11.3 ± 2.0 kg m−2; Nit = 10.0 ± 0.8 kg m−2; Control = 4.6 ± 0.6 kg m−2) demonstrate that artificial wetlands of S. neei can be used for wastewater treatment in saline aquaculture in South America.